CONTENTS. 



Preface toffth edition iii 



Preface to earlier editions ........ vi 



CHAPTER I. Introductory. General description of agricultural eartJis 

 and soils. Physical and chemical constituents of soils. 



Difficulties of defining earths and soils, 17, 18. Chemists' definitions unsuitable for agricul- 

 ture, 18. Agricultural earths, 19. Siliceous earth, 19. Aluminous, 20. Calcareous, 20; 

 different definitions thereof by authors, 22. Chalk, 23. Magnesian earth, 24. Humus, 

 25. Soils and sub-soils, 25. Constituents of soils, 26, and of sub-soils, 27. Physical and 

 chemical constituents, 28, 29, 30. Nomenclature and definitions of soils, 31, 32, 33. 



CHAP. II. On the soils and state of agriculture of the Tide-water Dis- 

 trict of Virginia. 



General features of the district and its soils, 34, 36. Ridges, 35. Slopes, 35, 36. River mar- 

 gins and alluvial lands, 36. Exhausting tillage and small products, 36. Decreasing popu- 

 lation, 38. Hopeless of improvement under existing circumstances, 39. 



CHAP. III. The different capacities of soils for improvement. 



Five principal propositions stated for discussion, 39. Natural fertility defined, 40. Perma- 

 nency of either fertile or sterile character of different countries and soils, 41. Land natu- 

 rally poor not capable of being enriched by putrescent manures, 41, 42. Opposing opinions 

 and authorities, 43, 45. Facts in support, 44. The degree of original fertility the limit of 

 profitable improvement by putrescent manures, 46, 47. 



CHAP. IV. Effects of the presence of calcareous earth. 



Calcareous earth not found in our poor soils, 48. Its presence indicating great fertility, 48. 

 Natural growths on shelly and on poor soils, 49. All authority supports the general pre- 

 sence of carbonate of lime in soils, 50 to 53, Soils rarely calcareous in Virginia, 54. Re- 

 cent confirming testimony (note), 54, 55. 



CHAP. V. Results of chemical examinations of various soils. 



Methods for testing the presence or absence of carbonate of lime in soils, 56 to 59. Various 

 soils tested calcareous, 59 to 61. All known calcareous soils rich, and no poor soil calca- 

 reous, 61. 



CHAP. VI. Chemical examination of rich soils containing no calcareous 



earth. 



Rich river lands, 62 and also mountain lime-stone soils, 63 to 65. Prairie soils of Alabama 

 generally highly calcareous, or super-calcareous, 66, 67. 



CHAP. VII. Proofs of the existence of acid and neutral soils. 



Lime in some form present in every soil, 08. Acid not considered an ingredient of soil by 

 any -writers of authority, and denied by others, 69, 70. Proofs of acidity in soil, 70. 

 Growth of acid plants, 71. Nourished best by dead acid plants, 71, 72. By other putres- 

 cent manures, 72. A.cid poisonous to cultivated plants, 73. Disappearance of carbonate of 

 lime in cultivated soils, 75 to 80. Wood ashes contain lime, 81, 82. Scientific confirmation 

 of acid in soil, 82 to 88. Discovery of humic acid, 83 ; its properties, 86. Successive natu- 

 ral changes of chemical character in soils, 88, 89, 90. Testimony of Loudon of originality 

 of doctrine (note), 91. 



CHAP. VIII. The mode of operation by which calcareous earth increases 

 the fertility and productiveness of soils. 



gilicious and aluminous earths have no chemical power to retain putrcprent manure, 92, 

 93, 91. Calcareous earth has such power, and how, 94, 95. Examples of combining opera- 

 tions, 95. Power of fixing fertilizing matters in soils, 96. Power of neutralizing injurious 

 acids, 97, 93. Power of altering and improving texturo of both sandy and clayey soils, 98, 



